A commonly available design for a refrigeration appliance, particularly one for consumer use, includes a cabinet that contains a freezer compartment and a fresh food compartment. These compartments may be arranged e.g., side by side or may include one positioned over the other. Refrigeration systems are typically utilized to cool the compartments.
In one example of a conventional design, the evaporator of a refrigeration system is positioned in the freezer compartment where a fan moves air in the freezer compartment across the evaporator to freeze the contents of the freezer compartment. A damper positioned between the freezer compartment and the fresh food compartment is used to feed a portion of the air over to the fresh food compartment for cooling its contents. In another example of a conventional design, a refrigeration system may utilize multiple evaporators, such as an evaporator to freeze the contents of the freezer compartment and an evaporator to cool the contents of the fresh food compartment.
Presently known multiple evaporator systems can, however, have disadvantages. For example, when one or both evaporators are off, frost can accumulate on the evaporator(s). This frost can reduce the efficiency of the associated evaporator. One effort to reduce or eliminate frost has been to utilize a heater, such as an electric heater, to heat the evaporator(s) when they are not operating. However, the addition of a heater to the system adds cost and complexity to the system, and increases the energy consumption of the system.
Accordingly, improved refrigerator appliances and refrigeration systems therefore are desired. In particular, cost- and energy-effective refrigerator appliances and refrigeration systems which reduce evaporator frost build-up would be advantageous.